Method for performing wireless charging control with aid of admittance detection, and associated apparatus

ABSTRACT

A method for performing wireless charging control and an associated apparatus are provided, where the method may include: performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter; generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes may include a power loss index indicating power loss of a wireless charging operation performed by the wireless charging transmitter, and may further include an admittance-related index corresponding to any of a ratio of the driving current to the driving voltage or a reciprocal of the ratio of the driving current to the driving voltage; and performing wireless charging foreign object detection (FOD) according to the set of indexes.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/955,459, which was filed on Mar. 19, 2014, and is included herein byreference. This application further claims the benefit of U.S.Provisional Application No. 61/928,093, which was filed on Jan. 16,2014, and is included herein by reference.

BACKGROUND

The present invention relates to foreign object detection (FOD) of awireless power transfer system such as a wireless charging system, andmore particularly, to a method for performing wireless charging control,and an associated apparatus.

FOD is a hot topic in the field of the wireless charging technologiessince a foreign object may endanger the user of a wireless chargingsystem. For example, a foreign object such as a Digital Versatile Disc(DVD) typically has a thin layer of metal. As the thin layer of metalmay be easily heated during wireless charging due to the eddy currents,the DVD can be regarded as a dangerous foreign object. Therefore, when aforeign object is detected, it is better to stop wireless charging.

According to the related art, a conventional FOD method based on powerloss detection is typically designed for an inductive wireless chargingsystem, rather than a resonant wireless charging system. In a situationwhere the conventional FOD method is applied to the inductive wirelesscharging system, the conventional FOD method can be used for detecting aforeign object near the inductive wireless charging system. However, ina situation where the conventional FOD method is applied to the resonantwireless charging system, some problems may be encountered. For example,it may be observed that there is only a slight difference between thepower loss in a first case in which a mobile phone is wirelessly chargedin the landscape orientation and the power loss in a second case inwhich this mobile phone is wirelessly charged in the portraitorientation and a DVD having the size of 8 centimeters (cm) ispositioned nearby, which means it is hard to distinguish one of the twocases (e.g. any of the cases A and B) from the other of the two cases.As a result, a false alarm (e.g. the first case is erroneouslyrecognized as the second case) or detection failure (e.g. the secondcase is erroneously recognized as the first case) may occur.

For the user's safety, the aforementioned detection failure should beprevented. In addition, for the user's convenience, the aforementionedfalse alarm should be prevented. Thus, when one is trying toimplementing a resonant wireless charging system such as that mentionedabove according to the conventional FOD method, there is a tradeoffbetween reducing the probability of the aforementioned false alarm andreducing the probability of the aforementioned detection failure. Thus,a novel method is required to enhance the wireless charging control of awireless charging system.

SUMMARY

It is an objective of the claimed invention to provide a method forperforming wireless charging control, and an associated apparatus, inorder to solve the above-mentioned problems.

It is another objective of the claimed invention to provide a method forperforming wireless charging control, and an associated apparatus, inorder to prevent dangerous foreign objects from making fire during awireless charging procedure.

It is another objective of the claimed invention to provide a method forperforming wireless charging control, and an associated apparatus, inorder to prevent non-dangerous foreign objects from interrupting awireless charging procedure.

According to at least one preferred embodiment, a method for performingwireless charging control is provided, where the method is applied to awireless charging transmitter. The method comprises the steps of:performing current detection and voltage detection to monitor a drivingcurrent and a driving voltage within the wireless charging transmitter,respectively, wherein the driving current and the driving voltage areutilized for driving a power output coil of the wireless chargingtransmitter; generating a set of indexes at least according to thedriving current and the driving voltage, wherein the set of indexescomprises a power loss index indicating power loss of a wirelesscharging operation performed by the wireless charging transmitter, andfurther comprises an admittance-related index corresponding to any of aratio of the driving current to the driving voltage or a reciprocal ofthe ratio of the driving current to the driving voltage; and performingwireless charging foreign object detection (FOD) according to the set ofindexes.

According to at least one preferred embodiment, an apparatus forperforming wireless charging control is provided, where the apparatuscomprises at least one portion of a wireless charging transmitter. Theapparatus comprises at least one detection circuit, and comprises a setof index generating circuits that is coupled to the aforementioned atleast one detection circuit, and further comprises a FOD strategy modulethat is coupled to the set of index generating circuits. Theaforementioned at least one detection circuit is arranged for performingcurrent detection and voltage detection to monitor a driving current anda driving voltage within the wireless charging transmitter,respectively, wherein the driving current and the driving voltage areutilized for driving a power output coil of the wireless chargingtransmitter. In addition, the set of index generating circuits isarranged for generating a set of indexes at least according to thedriving current and the driving voltage, wherein the set of indexescomprises a power loss index indicating power loss of a wirelesscharging operation performed by the wireless charging transmitter, andfurther comprises an admittance-related index corresponding to any of aratio of the driving current to the driving voltage or a reciprocal ofthe ratio of the driving current to the driving voltage. Additionally,the FOD strategy module is arranged for performing wireless charging FODaccording to the set of indexes.

According to at least one preferred embodiment, a method for performingwireless charging control is provided, where the method is applied to awireless charging transmitter. The method comprises the steps of:performing current detection and voltage detection to monitor a drivingcurrent and a driving voltage within the wireless charging transmitter,respectively, wherein the driving current and the driving voltage areutilized for driving a power output coil of the wireless chargingtransmitter; generating a set of indexes at least according to thedriving current and the driving voltage, wherein the set of indexescomprises a power loss index indicating power loss of a wirelesscharging operation performed by the wireless charging transmitter, andfurther comprises a current-related index corresponding to the drivingcurrent; and performing wireless charging foreign object detection (FOD)according to the set of indexes.

According to at least one preferred embodiment, a method for performingwireless charging control is provided, where the method is applied to awireless charging transmitter. The method comprises the steps of:performing current detection and voltage detection to monitor a drivingcurrent and a driving voltage within the wireless charging transmitter,respectively, wherein the driving current and the driving voltage areutilized for driving a power output coil of the wireless chargingtransmitter; generating a set of indexes at least according to thedriving current and the driving voltage, wherein the set of indexescomprises an admittance-related index corresponding to any of a ratio ofthe driving current to the driving voltage or a reciprocal of the ratioof the driving current to the driving voltage, and further comprises acurrent-related index corresponding to the driving current; andperforming wireless charging foreign object detection (FOD) according tothe set of indexes.

It is an advantage of the present invention that the present inventionmethod and the associated apparatus can accurately determine whether aforeign object is detected, and can accurately determine whether aforeign object is a dangerous foreign object or a non-dangerous foreignobject, and therefore the related art problems such as theaforementioned false alarm or the aforementioned detection failure canbe prevented. More particularly, in a situation where the wirelesscharging transmitter is a resonant wireless charging transmitter, thepresent invention method and the associated apparatus can properlyperform FOD with aid of admittance detection and/or impedance detection,and can temporarily stop a wireless charging procedure when needed, andtherefore can prevent dangerous foreign objects from making fire duringthe wireless charging procedure and can prevent non-dangerous foreignobjects from interrupting the wireless charging procedure. As a result,both of the performance of the wireless charging transmitter and thesafety of the user of the wireless charging transmitter can beguaranteed.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an apparatus for performing wireless chargingcontrol according to an embodiment of the present invention.

FIG. 2 is a diagram of a wireless power transfer system according to anembodiment of the present invention.

FIG. 3 illustrates a flowchart of a method for performing wirelesscharging control according to an embodiment of the present invention.

FIG. 4 illustrates a multi-index control scheme involved with the methodshown in FIG. 3 according to an embodiment of the present invention.

FIG. 5 illustrates a multi-index control scheme involved with the methodshown in FIG. 3 according to another embodiment of the presentinvention.

FIG. 6 illustrates a foreign object detection (FOD) zone involved withthe method shown in FIG. 3 according to an embodiment of the presentinvention.

FIG. 7 illustrates a FOD strategy control scheme involved with themethod shown in FIG. 3 according to an embodiment of the presentinvention.

FIG. 8 illustrates a wireless charging recovery scheme involved with themethod shown in FIG. 3 according to an embodiment of the presentinvention.

FIG. 9 illustrates a random mode device control scheme involved with themethod shown in FIG. 3 according to an embodiment of the presentinvention.

FIG. 10 illustrates a steady state control scheme involved with themethod shown in FIG. 3 according to an embodiment of the presentinvention.

FIG. 11 illustrates an emergency protection control scheme involved withthe method shown in FIG. 3 according to an embodiment of the presentinvention.

DETAILED DESCRIPTION

Certain terms are used throughout the following description and claims,which refer to particular components. As one skilled in the art willappreciate, electronic equipment manufacturers may refer to a componentby different names. This document does not intend to distinguish betweencomponents that differ in name but not in function. In the followingdescription and in the claims, the terms “include” and “comprise” areused in an open-ended fashion, and thus should be interpreted to mean“include, but not limited to . . . ”. Also, the term “couple” isintended to mean either an indirect or direct electrical connection.Accordingly, if one device is coupled to another device, that connectionmay be through a direct electrical connection, or through an indirectelectrical connection via other devices and connections.

Please refer to FIG. 1, which illustrates a diagram of an apparatus 100for performing wireless charging control according to an embodiment ofthe present invention, where the apparatus 100 may comprise at least oneportion (e.g. a portion or all) of a wireless charging device. Forexample, the apparatus 100 may comprise a portion of the wirelesscharging device mentioned above, and more particularly, can be at leastone hardware circuit such as at least one integrated circuit (IC) withinthe wireless charging device and associated circuits thereof. In anotherexample, the apparatus 100 can be the whole of the wireless chargingdevice mentioned above. In another example, the apparatus 100 maycomprise a system comprising the wireless charging device mentionedabove (e.g. a wireless power transfer system comprising the wirelesscharging device). Examples of the wireless charging device may include,but not limited to, a wireless charging transmitter (which can also bereferred to as the transmitter, for brevity) such as a transmitter pad.For example, the aforementioned wireless charging transmitter such asthe transmitter pad can be utilized for wirelessly charging a wirelesscharging receiver (which can also be referred to as the receiver, forbrevity) such as a portable electronic device, where examples of theportable electronic device may include, but not limited to, a mobilephone (e.g. a multifunctional mobile phone), a personal digitalassistant (PDA), and a personal computer such as a laptop computer.

As shown in FIG. 1, the apparatus 100 may comprise at least onedetection circuit (e.g. one or more detection circuits), which can becollectively referred to as the detection circuit 110 in thisembodiment, and may further comprise an index generating module 120,which may comprise a set of index generating circuits that is coupled tothe aforementioned at least one detection circuit such as the detectioncircuit 110 shown in FIG. 1. For example, the number of index generatingcircuits within the set of index generating circuits mentioned above maybe equal to M (e.g. the notation M may represent a positive integer thatis greater than one). That is, the set of index generating circuits maycomprise M index generating circuits 122-1, 122-2, . . . , and 122-M. Inthis embodiment, the apparatus 100 may further comprise a foreign objectdetection (FOD) strategy module 130, where the FOD strategy module 130is coupled to the set of index generating circuits mentioned above, suchas the M index generating circuits 122-1, 122-2, . . . , and 122-M.

According to this embodiment, the aforementioned at least one detectioncircuit such as the detection circuit 110 shown in FIG. 1 is arrangedfor performing current detection and voltage detection to monitor adriving current I_(DRV) (not shown in FIG. 1) and a driving voltageV_(DRV) (not shown in FIG. 1) within the wireless charging transmitter,respectively, where the driving current I_(DRV) and the driving voltageV_(DRV) are utilized for driving a power output coil (not shown inFIG. 1) of the wireless charging transmitter. In addition, the set ofindex generating circuits mentioned above, such as the M indexgenerating circuits 122-1, 122-2, . . . , and 122-M, is arranged forgenerating a set of indexes such as M indexes 124-1, 124-2, . . . , and124-M at least according to the driving current I_(DRV) and the drivingvoltage V_(DRV), respectively. More particularly, the set of indexes maycomprise a power loss index indicating the power loss of a wirelesscharging operation performed by the wireless charging transmitter, andmay further comprise an admittance-related index corresponding to any ofthe ratio of the driving current I_(DRV) to the driving voltage V_(DRV)or the reciprocal of the ratio of the driving current I_(DRV) to thedriving voltage V_(DRV). For example, in a situation where theadmittance-related index corresponds to the ratio of the driving currentI_(DRV) to the driving voltage V_(DRV), the admittance-related index canbe an admittance deviation index. In another example, in a situationwhere the admittance-related index corresponds to the reciprocal of theratio of the driving current I_(DRV) to the driving voltage V_(DRV), theadmittance-related index can be an impedance deviation index.Additionally, the FOD strategy module 130 is arranged for performingwireless charging FOD according to the set of indexes mentioned above,such as the M index generating circuits 122-1, 122-2, . . . , and 122-M.

As mentioned, the set of indexes may comprise the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter, and may further comprise theadmittance-related index corresponding to any of the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV) or the reciprocalof the ratio of the driving current I_(DRV) to the driving voltageV_(DRV). This is for illustrative purposes only, and is not meant to bea limitation of the present invention. In some examples, the set ofindexes may further comprise a current-related index corresponding tothe driving current I_(DRV).

In some examples, the set of indexes may comprise the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter, and may further comprise thecurrent-related index corresponding to the driving current I_(DRV),where it is unnecessary to generate the admittance-related indexcorresponding to any of the ratio of the driving current I_(DRV) to thedriving voltage V_(DRV) or the reciprocal of the ratio of the drivingcurrent I_(DRV) to the driving voltage V_(DRV).

In some examples, the set of indexes may comprise the admittance-relatedindex corresponding to any of the ratio of the driving current I_(DRV)to the driving voltage V_(DRV) or the reciprocal of the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV), and may furthercomprise the current-related index corresponding to the driving currentI_(DRV), where it is unnecessary to generate the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter.

FIG. 2 is a diagram of a wireless power transfer system 200 according toan embodiment of the present invention. As shown in FIG. 2, the wirelesspower transfer system 200 may comprise a wireless charging transmitter210 (labeled “Tx” in FIG. 2, for brevity) and a wireless chargingreceiver 220 (labeled “Rx” in FIG. 2, for brevity), where the wirelesscharging transmitter 210 shown in FIG. 2 can be taken as an example ofthe wireless charging transmitter mentioned in the embodiment shown inFIG. 1, and the wireless charging receiver 220 can be taken as anexample of the wireless charging receiver mentioned in the embodimentshown in FIG. 1.

According to this embodiment, the wireless charging transmitter 210 maycomprise the detection circuit 110 shown in FIG. 1, and the detectioncircuit 110 of this embodiment may comprise a voltage meter 112 (labeled“VM” in FIG. 2, for brevity) and a current meter. For example, thecurrent meter of this embodiment may comprise a voltage meter 114(labeled “VM” in FIG. 2, for brevity) and a sensing resistor R_(S). Inaddition to the detection circuit 110, the wireless charging transmitter210 may comprise a driving circuit 212, a matching circuit 214, and apower output coil 218, where the power output coil 218 shown in FIG. 2can be taken as an example of the power output coil mentioned in theembodiment shown in FIG. 1. In addition, the wireless charging receiver220 may comprise a power input coil 228, and may further comprise awireless charging receiver circuit (labeled “Rx CKT” in FIG. 2, forbrevity) for performing wireless charging control, where the wirelesscharging receiver circuit may comprise some components such as somehardware circuits. For example, in a situation where a portableelectronic device such as that mentioned in the embodiment shown in FIG.1 does not have the capability of being wirelessly charged (e.g. thisportable electronic device does not have any power input coil forwirelessly receiving power from the wireless charging transmitter 210),the wireless charging receiver 220 can be a charging module, and can bearranged for charging this portable electronic device by utilizing thepower that is wirelessly obtained from the wireless charging transmitter210. More particularly, when needed, the charging module can beelectrically connected to the portable electronic device to charge thisportable electronic device by using at least one portion (e.g. a portionor all) of the power that is wirelessly obtained from the wirelesscharging transmitter 210, where the charging module can be detached fromthis portable electronic device when charging this portable electronicdevice in this manner is not required. This is for illustrative purposesonly, and is not meant to be a limitation of the present invention. Insome examples, in a situation where a portable electronic device such asthat mentioned in the embodiment shown in FIG. 1 has the capability ofbeing wirelessly charged, the wireless charging receiver 220 maycomprise the whole of this portable electronic device. Thus, in additionto the aforementioned wireless charging receiver circuit (labeled “RxCKT” in FIG. 2), the wireless charging receiver 220 may further compriseat least one processor (e.g. one or more processors), the associatedcontrol circuit thereof, and at least one storage module (e.g. a harddisk drive (HDD), and/or a non-volatile (NV) memory such as a Flashmemory).

In this embodiment, the driving circuit 212 is arrange for generatingthe driving voltage V_(DRV) and the driving current I_(DRV), and isarrange for utilizing the driving voltage V_(DRV) and the drivingcurrent I_(DRV) to drive the power output coil 218 through the matchingcircuit 214, in order to wirelessly output power toward at least onewireless charging receiver (e.g. one or more wireless chargingreceivers) outside the wireless charging transmitter 210, such as thewireless charging receiver 220 shown in FIG. 2. As shown in FIG. 2, thetwo input terminals of the voltage meter 112 are coupled to the twooutput terminals N11 and N12 of the driving circuit 212, respectively,and is arranged for detecting the driving voltage V_(DRV) between thetwo output terminals N11 and N12. In addition, the two input terminalsof the voltage meter 114 are coupled to the two terminals of the sensingresistor R_(S), and is arranged for detecting the voltage differencebetween the two terminals of the sensing resistor R_(S). Thus, thedetection circuit 110 may perform a calculation operation according tothe voltage difference between the two terminals of the sensing resistorR_(S) and the resistance value of the sensing resistor R_(S), and moreparticularly, may divide the voltage difference between the twoterminals of the sensing resistor R_(S) by the resistance value of thesensing resistor R_(S), to detect the driving current I_(DRV). Inpractice, the matching circuit 214 may comprise some impedancecomponents such as some capacitors, for enhancing the power outputperformance of the power output coil 218, where the two input terminalsN31 and N32 of the matching circuit 214 are coupled to the two outputterminals N21 and N22 of the matching circuit 214, respectively.

For better comprehension, some implementation details of theaforementioned wireless charging receiver circuit (labeled “Rx CKT” inFIG. 2) can be described as follows. The wireless charging receivercircuit may comprise a matching circuit and a rectifier that arepositioned on a power transfer path of the wireless charging receivercircuit. For example, this matching circuit may comprise some impedancecomponents such as some capacitors, for enhancing the power inputperformance of the power input coil 228, and the rectifier can bearranged for converting the alternating current (AC) power obtained fromthe power input coil 228 through this matching circuit into the directcurrent (DC) power, and more particularly, into a DC output voltage,where the DC output voltage output from the rectifier can be utilized bythe portable electronic device. This is for illustrative purposes only,and is not meant to be a limitation of the present invention. In anotherexample, the wireless charging receiver circuit mentioned above mayfurther comprise a low dropout (LDO) regulator that is also positionedon the power transfer path of the wireless charging receiver circuit,and the LDO regulator is arranged for regulating the DC output voltageoutput from the rectifier, to generate a regulated output voltage forbeing utilized by the portable electronic device. In some examples, thewireless charging receiver circuit may comprise a detection module,whose architecture maybe similar to that of the detection circuit 110shown in FIG. 2, and therefore can be utilized for detecting orestimating the received power of the wireless charging receiver 220(e.g. the power that the wireless charging receiver 220 wirelesslyobtains from the wireless charging transmitter 210). More particularly,the wireless charging receiver 220 may send at least one packet (e.g.one or more packets) toward the wireless charging transmitter 210through the power input coil 228, where the aforementioned at least onepacket may carry received power information indicating theaforementioned received power of the wireless charging receiver 220. Asa result, the wireless charging transmitter 210 may receive theaforementioned at least one packet from the wireless charging receiver220 through the power output coil 218, and may determine the receivedpower of the wireless charging receiver 220 according to theaforementioned received power information carried by the aforementionedat least one packet.

Based on the architecture shown in FIG. 2, the apparatus 100 of thisembodiment may comprise at least one portion (e.g. a portion or all) ofthe wireless power transfer system 200. For example, the apparatus 100may comprise a portion of the wireless power transfer system 200, andmore particularly, may comprise a portion of the wireless chargingtransmitter 210, which means the apparatus 100 may comprise somecomponents within the wireless charging transmitter 210 shown in FIG. 2.In another example, the apparatus 100 may comprise a portion of thewireless power transfer system 200, and more particularly, can be thewhole of the wireless charging transmitter 210, which means theapparatus 100 may comprise all components within the wireless chargingtransmitter 210. In another example, the apparatus 100 can be the wholeof the wireless power transfer system 200.

In addition, based on the architecture shown in FIG. 2, electric powermay be transferred from the left side (e.g. the DC power input into thedriving circuit 212 shown in the leftmost of FIG. 2) to the right side(e.g. the DC power provided by the wireless charging receiver circuitshown in the rightmost of FIG. 2, such as the DC power to be utilized bythe portable electronic device) stage by stage, where power loss mayoccur in some of the stages in this architecture. In a situation where aforeign object, such as a metallic object or magnetic object,occasionally drops nearby and starts absorbing energy from the wirelesscharging transmitter 210 of this embodiment, the wireless chargingreceiver 220 (more particularly, a controller therein) may detect orestimate the received power of the wireless charging receiver 220 (e.g.the power that the wireless charging receiver 220 wirelessly obtainsfrom the wireless charging transmitter 210) and send a received powerreport corresponding to the received power (e.g. a received power reportpacket such as any packet within the aforementioned at least one packet,where the received power report packet may carry an estimated value ofthe received power) to the wireless charging transmitter 210 throughrelated components (e.g. a communications module in the wirelesscharging receiver 220, the aforementioned matching circuit of thewireless charging receiver 220, the power input coil 228, and the poweroutput coil 218). As a result, the apparatus 100 may perform power lossdetection according to the driving current I_(DRV) and the drivingvoltage V_(DRV) and according to the received power of the wirelesscharging receiver 220, to generate the power loss index mentioned above.Further, the wireless charging transmitter 210 (more particularly, theFOD strategy module 130 in the apparatus 100 shown in FIG. 1) mayperform the aforementioned wireless charging FOD according to the set ofindexes mentioned above, such as the M index generating circuits 122-1,122-2, . . . , and 122-M. Under control of the FOD strategy module 130,the wireless charging transmitter 210 may temporarily stop outputtingpower toward the wireless charging receiver 220 when needed, where therelated art problems such as the aforementioned false alarm or theaforementioned detection failure can be prevented.

More particularly, in a situation where the wireless chargingtransmitter 210 is a resonant wireless charging transmitter, theapparatus 100 (and the associated method thereof) can properly performFOD with aid of admittance detection and/or impedance detection, and cantemporarily stop a wireless charging procedure when needed, andtherefore can prevent dangerous foreign objects from making fire duringthe wireless charging procedure and can prevent non-dangerous foreignobjects from interrupting the wireless charging procedure. As a result,both of the performance of the wireless power transfer system 200 (moreparticularly, the performance of the wireless charging transmitter 210)and the safety of the user of the wireless power transfer system 200(more particularly, the safety of the user of the wireless chargingtransmitter 210) can be guaranteed.

FIG. 3 illustrates a flowchart of a method 300 for performing wirelesscharging control according to an embodiment of the present invention.The method 300 shown in FIG. 3 can be applied to the apparatus 100 shownin FIG. 1 (more particularly, the wireless power transfer system 200 ofthe embodiment shown in FIG. 2), and can be applied to the FOD strategymodule 130 thereof. The method can be described as follows.

In Step 310, the aforementioned at least one detection circuit such asthe detection circuit 110 in any of the embodiments respectively shownin FIG. 1 or FIG. 2 performs the aforementioned current detection andthe aforementioned voltage detection to monitor the driving currentI_(DRV) and the driving voltage V_(DRV) within the wireless chargingtransmitter 210, respectively, where the driving current I_(DRV) and thedriving voltage V_(DRV) are utilized for driving the power output coil218 of the wireless charging transmitter 210.

In Step 320, the set of index generating circuits mentioned above, suchas the M index generating circuits 122-1, 122-2, . . . , and 122-M shownin FIG. 1, generates the set of indexes such as the M indexes 124-1,124-2, . . . , and 124-M shown in FIG. 1 at least according to thedriving current I_(DRV) and the driving voltage V_(DRV), respectively.For example, the set of indexes may comprise the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter 210, and may further comprise theadmittance-related index corresponding to any of the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV) or the reciprocalof the ratio of the driving current I_(DRV) to the driving voltageV_(DRV). This is for illustrative purposes only, and is not meant to bea limitation of the present invention. In some examples, the set ofindexes may further comprise a current-related index corresponding tothe driving current I_(DRV).

In some examples, the set of indexes may comprise the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter, and may further comprise thecurrent-related index corresponding to the driving current I_(DRV),where it is unnecessary to generate the admittance-related indexcorresponding to any of the ratio of the driving current I_(DRV) to thedriving voltage V_(DRV) or the reciprocal of the ratio of the drivingcurrent I_(DRV) to the driving voltage V_(DRV).

In some examples, the set of indexes may comprise the admittance-relatedindex corresponding to any of the ratio of the driving current I_(DRV)to the driving voltage V_(DRV) or the reciprocal of the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV), and may furthercomprise the current-related index corresponding to the driving currentI_(DRV), where it is unnecessary to generate the power loss indexindicating the power loss of the wireless charging operation performedby the wireless charging transmitter.

In Step 330, the FOD strategy module 130 performs the aforementionedwireless charging FOD according to the set of indexes mentioned above,such as the M index generating circuits 122-1, 122-2, . . . , and 122-M.More particularly, the FOD strategy module 130 may determine a set ofthreshold corresponding to a set of FOD strategy control parametersaccording to a predetermined relationship between the set of thresholdand the set of FOD strategy control parameters, and may compare the setof indexes with the set of threshold to generate a set of comparisonresults, respectively, and may further generate a wireless chargingcontrol signal (e.g. the output of the FOD strategy module 130 shown inFIG. 1) according to the set of comparison results, for controllingwhether to temporarily stop wireless charging or not. For example, thepredetermined relationship between the set of threshold and the set ofFOD strategy control parameters may be obtained from a database that isprepared in advance within the wireless charging transmitter 210 (or alook up table (LUT) that is prepared in advance within the wirelesscharging transmitter 210).

In practice, for better flexibility of calibrating at least one FODstrategy (e.g. one or more FOD strategies) of the FOD strategy module130, the FOD strategy module 130 may comprise at least one database(e.g. one or more databases) which may comprise the database mentionedabove, and the aforementioned at least one database can be utilized forstoring strategy information of the aforementioned at least one FODstrategy. More particularly, according to the strategy information ofthe aforementioned at least one FOD strategy, such as the strategyinformation that is stored in the aforementioned at least one database,the FOD strategy module 130 may dynamically adjust at least oneadjustable threshold (e.g. one or more adjustable thresholds), which canbe utilized for performing the aforementioned wireless charging FODaccording to the set of indexes mentioned above. This is forillustrative purposes only, and is not meant to be a limitation of thepresent invention. In some examples, the aforementioned at least onedatabase can be positioned outside the FOD strategy module 130, and theFOD strategy module 130 may obtain the strategy information of theaforementioned at least one FOD strategy from the aforementioned atleast one database, where the aforementioned at least one database canbe positioned within the wireless charging transmitter 210.

In some examples, the FOD strategy module 130 may comprise at least oneLUT (e.g. one or more LUTs) which may comprise the LUT mentioned above,and the aforementioned at least one LUT can be utilized for storingstrategy information of the aforementioned at least one FOD strategy.More particularly, according to the strategy information of theaforementioned at least one FOD strategy, such as the strategyinformation that is stored in the aforementioned at least one LUT, theFOD strategy module 130 may dynamically adjust the aforementioned atleast one adjustable threshold (e.g. one or more adjustable thresholds),which can be utilized for performing the aforementioned wirelesscharging FOD according to the set of indexes mentioned above. This isfor illustrative purposes only, and is not meant to be a limitation ofthe present invention. In some examples, the aforementioned at least oneLUT can be positioned outside the FOD strategy module 130, and the FODstrategy module 130 may obtain the strategy information of theaforementioned at least one FOD strategy from the aforementioned atleast one LUT, where the aforementioned at least one LUT can bepositioned within the wireless charging transmitter 210.

In some examples, the FOD strategy module 130 may comprise both of theaforementioned at least one database (e.g. one or more databases) andthe aforementioned at least one LUT (e.g. one or more LUTs), and theaforementioned at least one database and the aforementioned at least oneLUT can be utilized for storing the strategy information of theaforementioned at least one FOD strategy. More particularly, accordingto the strategy information of the aforementioned at least one FODstrategy, such as the strategy information that is stored in theaforementioned at least one database and the strategy information thatis stored in the aforementioned at least one LUT, the FOD strategymodule 130 may dynamically adjust the aforementioned at least oneadjustable threshold (e.g. one or more adjustable thresholds), which canbe utilized for performing the aforementioned wireless charging FODaccording to the set of indexes mentioned above. This is forillustrative purposes only, and is not meant to be a limitation of thepresent invention. In some examples, the aforementioned at least onedatabase and/or the aforementioned at least one LUT (e.g. theaforementioned at least one database, or the aforementioned at least oneLUT, or both of the aforementioned at least one database and theaforementioned at least one LUT) can be positioned outside the FODstrategy module 130, and the FOD strategy module 130 may obtain thestrategy information of the aforementioned at least one FOD strategyfrom the aforementioned at least one database and the aforementioned atleast one LUT, where the aforementioned at least one database and theaforementioned at least one LUT can be positioned within the wirelesscharging transmitter 210.

In some examples, for better flexibility of calibrating theaforementioned at least one FOD strategy (e.g. one or more FODstrategies) of the FOD strategy module 130, the FOD strategy module 130can be implemented with a processing circuit running a set of programcodes, such as a controller or a processor, where the set of programcodes can be prepared in advance and can be stored in a storage modulewithin the wireless charging transmitter 210 (e.g. a non-volatile (NV)memory such as a Flash memory or any of other types of NV memories, or ahard disk drive (HDD)) in advance.

Please note that the operation of Step 310, the operation of Step 320,and the operation of Step 330 are illustrated in FIG. 3, respectively.This is for illustrative purposes only, and is not meant to be alimitation of the present invention. According to some variations ofthis embodiment, at least one portion (e.g. a portion or all) of theoperation of Step 310, at least one portion (e.g. a portion or all) ofthe operation of Step 320, and/or at least one portion (e.g. a portionor all) of the operation of Step 330 can be performed at the same time.For example, at least one portion (e.g. a portion or all) of theoperation of Step 310 and at least one portion (e.g. a portion or all)of the operation of Step 320 can be performed at the same time. Inanother example, at least one portion (e.g. a portion or all) of theoperation of Step 320 and at least one portion (e.g. a portion or all)of the operation of Step 330 can be performed at the same time.

For better comprehension, some implementation details regarding the setof indexes mentioned in Step 320 can be described as follows. Regardingthe power loss index mentioned above, the apparatus 100 may determinethe charging power output from the wireless charging transmitter 210(e.g. the power that the wireless charging transmitter 210 wirelesslyoutputs toward the aforementioned at least one wireless chargingreceiver such as the wireless charging receiver 220) according to thedriving current I_(DRV) and the driving voltage V_(DRV), where thecharging power output from the wireless charging transmitter 210 can bereferred to as the transmitter power (which can also be referred to asthe Tx power in some embodiments, for brevity). For example, theapparatus 100 may determine the transmitter power by calculating theproduct of the driving current I_(DRV) and the driving voltage V_(DRV).In addition to the transmitter power, the apparatus 100 may determinethe received power of the aforementioned at least one wireless chargingreceiver according to at least one received power report obtained fromthe aforementioned at least one wireless charging receiver (e.g. theaforementioned received power report obtained from the wireless chargingreceiver 220), where the received power of the aforementioned at leastone wireless charging receiver can be referred to as the receiver power(which can also be referred to as the Rx power in some embodiments, forbrevity). In addition, the apparatus 100 (more particularly, an indexgenerating circuit within the M index generating circuits 122-1, 122-2,. . . , and 122-M, such as the index generating circuit 122-1) mayfurther generate the power loss index according to the charging poweroutput from the wireless charging transmitter 210 (e.g. the power thatthe wireless charging transmitter 210 wirelessly outputs toward theaforementioned at least one wireless charging receiver such as thewireless charging receiver 220) and according to the received power ofthe aforementioned at least one wireless charging receiver. In someembodiments, the power loss index can be referred to as the power loss,for brevity.

Regarding the admittance-related index mentioned above, in a situationwhere the admittance-related index corresponds to the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV), the apparatus100 may determine the received power of the aforementioned at least onewireless charging receiver according to the aforementioned at least onereceived power report obtained from the aforementioned at least onewireless charging receiver, and may determine a normalized transmitteradmittance parameter (which can also be referred to as the normalized Txadmittance, for brevity) corresponding to the received power of theaforementioned at least one wireless charging receiver according to apredetermined relationship between the normalized transmitter admittanceparameter and the received power of the aforementioned at least onewireless charging receiver. For example, the predetermined relationshipbetween the normalized transmitter admittance parameter and the receivedpower of the aforementioned at least one wireless charging receiver maybe obtained from a database such as that mentioned above (or another LUTin the wireless charging transmitter 210) within the wireless chargingtransmitter 210. In addition, a specific index generating circuit withinthe set of index generating circuits (e.g. an index generating circuitwithin the M index generating circuits 122-1, 122-2, . . . , and 122-M,such as the index generating circuit 122-3) may calculate a differencebetween the ratio of the driving current I_(DRV) to the driving voltageV_(DRV) and the normalized transmitter admittance parameter mentionedabove to generate the admittance-related index, where the ratio of thedriving current I_(DRV) to the driving voltage V_(DRV) can be referredto as the transmitter admittance (which can also be referred to as theTx admittance in some embodiments, for brevity). Please note that, insome embodiments, the admittance-related index corresponding to theratio of the driving current I_(DRV) to the driving voltage V_(DRV) canbe referred to as the current deviation, for better comprehension.

In addition, regarding the admittance-related index mentioned above, ina situation where the admittance-related index corresponds to thereciprocal of the ratio of the driving current I_(DRV) to the drivingvoltage V_(DRV), the apparatus 100 may determine the received power ofthe aforementioned at least one wireless charging receiver according tothe aforementioned at least one received power report obtained from theaforementioned at least one wireless charging receiver, and maydetermine a normalized transmitter impedance parameter (which can alsobe referred to as the normalized Tx impedance, for brevity)corresponding to the received power of the aforementioned at least onewireless charging receiver according to a predetermined relationshipbetween the normalized transmitter impedance parameter and the receivedpower of the aforementioned at least one wireless charging receiver. Forexample, the predetermined relationship between the normalizedtransmitter impedance parameter and the received power of theaforementioned at least one wireless charging receiver may be obtainedfrom a database such as that mentioned above (or another LUT in thewireless charging transmitter 210) within the wireless chargingtransmitter 210. In addition, a specific index generating circuit withinthe set of index generating circuits (e.g. an index generating circuitwithin the M index generating circuits 122-1, 122-2, . . . , and 122-M,such as the index generating circuit 122-3) may calculate a differencebetween the reciprocal of the ratio of the driving current I_(DRV) tothe driving voltage V_(DRV) and the normalized transmitter impedanceparameter mentioned above to generate the admittance-related index,where the reciprocal of the driving current I_(DRV) to the drivingvoltage V_(DRV) (i.e. the ratio of the driving voltage V_(DRV) to thedriving current I_(DRV)) can be referred to as the transmitter impedance(which can also be referred to as the Tx impedance in some embodiments,for brevity). Please note that, in some embodiments, theadmittance-related index corresponding to the reciprocal of the ratio ofthe driving current I_(DRV) to the driving voltage V_(DRV) can bereferred to as the impedance deviation, for better comprehension.

Regarding the current-related index mentioned above, please note thatthe current-related index is different from the admittance-relatedindex. The apparatus 100 may determine the received power of theaforementioned at least one wireless charging receiver according to theaforementioned at least one received power report obtained from theaforementioned at least one wireless charging receiver, and maydetermine a normalized transmitter current parameter (which can also bereferred to as the normalized Tx current, for brevity) corresponding tothe received power of the aforementioned at least one wireless chargingreceiver according to a predetermined relationship between thenormalized transmitter current parameter and the received power of theaforementioned at least one wireless charging receiver. For example, thepredetermined relationship between the normalized transmitter currentparameter and the received power of the aforementioned at least onewireless charging receiver may be obtained from a database such as thatmentioned above (or another LUT in the wireless charging transmitter210) within the wireless charging transmitter 210. In addition, aspecific index generating circuit within the set of index generatingcircuits (e.g. an index generating circuit within the M index generatingcircuits 122-1, 122-2, . . . , and 122-M, such as the index generatingcircuit 122-2) may calculate a difference between the driving currentI_(DRV) and the normalized transmitter current parameter mentioned aboveto generate the current-related index, where the driving current I_(DRV)can be referred to as the transmitter current (which can also bereferred to as the Tx current in some embodiments, for brevity). Pleasenote that, in some embodiments, the current-related index can bereferred to as the current deviation, for better comprehension.

According to some embodiments, the apparatus 100 may generate a warningcontrol signal according to at least one portion of comparison resultswithin the set of comparison results mentioned above, where the warningcontrol signal is utilized for controlling a warning user interface (UI)of the wireless charging transmitter 210 to indicate whether a foreignobject is a dangerous foreign object or a non-dangerous foreign object.Examples of the warning UI mentioned above may include, but not limitedto, at least one light emitting diode (LED) (e.g. one or more LEDs),where the aforementioned at least one LED can be referred to as thewarning LED.

According to some embodiments, the set of FOD strategy controlparameters mentioned above may comprise a received power parameter,where the received power parameter corresponds to the received power ofthe aforementioned at least one wireless charging receiver. Moreparticularly, the set of FOD strategy control parameters may furthercomprise a wireless charging receiver count parameter, where thewireless charging receiver count parameter represents the number ofwireless charging receivers within the aforementioned at least onewireless charging receiver. For example, the set of FOD strategy controlparameters may further comprise at least one device type parameter,where the aforementioned at least one device type parameter correspondsto a transmitter type (which can be referred to as Tx type in someembodiments, for brevity) of the wireless charging transmitter 210 or atleast one receiver type (which can be referred to as Rx type in someembodiments, for brevity) of the aforementioned at least one wirelesscharging receiver (e.g. a receiver type of the wireless chargingreceiver 220).

According to some embodiments, a specific wireless charging receiverwithin the aforementioned at least one wireless charging receiver maydetermine at least one random value for controlling timing of packettransmission regarding at least one wireless charging report of thespecific wireless charging receiver. In addition, based on theaforementioned at least one random value, the specific wireless chargingreceiver may send at least one random phase-delay packet, where eachrandom phase-delay packet of the aforementioned at least one randomphase-delay packet may have a random phase-delay with respect to a timeslot of a series of time slots along the time axis, and theaforementioned at least one random phase-delay packet can be utilizedfor carrying information of the aforementioned at least one wirelesscharging report. Additionally, the apparatus 100 may accumulate packetinformation of a plurality of packets (e.g. a plurality of receivedpower report packets such as that mentioned above) in a predefinedperiod to generate an accumulation value, where the plurality of packetscomprises the aforementioned at least one random phase-delay packet sentby the specific wireless charging receiver, and the length of thepredefined period is greater than or equal to twice the length of thetime slot. Further, the apparatus 100 may determine the wirelesscharging receiver count parameter mentioned above according to theaccumulation value. More particularly, the apparatus 100 may perform atleast one filtering operation on the accumulation value to generate thewireless charging receiver count parameter.

According to some embodiments, the apparatus 100 may access a FODcontrol database that is prepared in advance. In addition, the FODcontrol database may indicate at least one predetermined zone, such as aFOD zone, on a coordinate plane of (Rx_power, Tx_admittance), in whichthe coordinate Rx_power may represent the received power of theaforementioned at least one wireless charging receiver and thecoordinate Tx_admittance may represent the ratio of the driving currentI_(DRV) to the driving voltage V_(DRV), and the aforementioned at leastone predetermined zone may correspond to dangerous foreign objects ornon-dangerous foreign objects. Additionally, based on the FOD controldatabase, the apparatus 100 may determine whether to temporarily stopwireless charging or not according to the received power of theaforementioned at least one wireless charging receiver and the ratio ofthe driving current I_(DRV) to the driving voltage V_(DRV).

In practice, the FOD control database and the aforementioned databasecan be integrated into the same database. This is for illustrativepurposes only, and is not meant to be a limitation of the presentinvention. In some examples, the FOD control database and theaforementioned database can be implemented as individual databases,respectively.

In addition, the aforementioned at least one predetermined zone may beassociated with one or more adjustable thresholds to be utilized by theFOD strategy module 130, for example. This is for illustrative purposesonly, and is not meant to be a limitation of the present invention. Insome examples, it is unnecessary that the aforementioned at least onepredetermined zone are associated with one or more adjustable thresholdsto be utilized by the FOD strategy module 130.

According to some embodiments, the set of indexes mentioned in Step 320maybe generated in a steady state regarding the wireless chargingoperation performed by the wireless charging transmitter 210. Inaddition, the apparatus 100 may perform at least one steady statedetection within the wireless charging transmitter 210 to guarantee thatthe set of indexes is generated in the steady state.

According to some embodiments, the apparatus 100 may generate anotherset of indexes at least according to the driving current I_(DRV) and thedriving voltage V_(DRV), where the other set of indexes may comprise acurrent index indicating the driving current I_(DRV), and may furthercomprise an admittance index indicating the ratio of the driving currentI_(DRV) to the driving voltage V_(DRV). For better comprehension, thecurrent index mentioned above can also be referred to as the Tx current,and the admittance index can also be referred to as the Tx admittance.In addition, the apparatus 100 may perform the wireless charging FODaccording to the set of indexes and according to the other set ofindexes. For example, when the other set of indexes indicates that adangerous foreign object is detected, the apparatus 100 (moreparticularly, the FOD strategy module 130 therein) may immediately stopwireless charging, and may temporarily prevent utilizing the set ofindexes. Therefore, with aid of the other set of indexes the apparatus100 may perform emergency state FOD, where the set of indexes can betemporarily ignored in an emergency state of the wireless power transfersystem 200 (or an emergency state of the wireless charging transmitter210).

FIG. 4 illustrates a multi-index control scheme involved with the method300 shown in FIG. 3 according to an embodiment of the present invention.The curve in the sub-diagram (a) of FIG. 4 may indicate the power lossindex (which can be referred to as the power loss in this embodiment,for brevity) that varies with respect to time. In addition, the curve inthe sub-diagram (b) of FIG. 4 may indicate the current-related index(which can be referred to as the current deviation in this embodiment,for better comprehension) that varies with respect to time.Additionally, the curve in the sub-diagram (c) of FIG. 4 may indicatethe admittance-related index (which can be referred to as the admittancedeviation in this embodiment, for better comprehension) that varies withrespect to time, where the admittance-related index of this embodimentcorresponds to the ratio of the driving current I_(DRV) to the drivingvoltage V_(DRV).

For example, the time expressed by the horizontal axis of eachsub-diagram within the sub-diagrams (a), (b), and (c) of FIG. 4 can bemeasured in unit of second (sec), and the index values of the indexexpressed by the vertical axis of each sub-diagram within thesub-diagrams (a), (b), and (c) of FIG. 4 may have been scaled up orscaled down (e.g. by utilizing an associated amplifier in thecorresponding index generating circuit for generating this index withinthe index generating module 120), in order to prevent this index frombeing unusable and/or prevent this index from being truncated. This isfor illustrative purposes only, and is not meant to be a limitation ofthe present invention. In some examples, the unit of the time expressedby the horizontal axis of each sub-diagram within the sub-diagrams (a),(b), and (c) of FIG. 4 may vary. In some examples, it is unnecessary toprocess at least one index (e.g. one or more indexes) within the set ofindexes by scaling (e.g. scaling up or scaling down).

According to this embodiment, one or more of the wireless chargingreceiver 220 and a Digital Versatile Disc (DVD) having the size of 8centimeters (cm), such as the aforementioned DVD having the size of 8cm, can be selectively put onto the wireless charging transmitter 210 atdifferent time points. At first, there is no load of wireless charging(labeled “No load” in the sub-diagram (a) of FIG. 4, for brevity) andboth of the wireless charging receiver 220 and this DVD are not put ontothe wireless charging transmitter 210, and then the wireless chargingreceiver 220 is put onto the wireless charging transmitter 210 in theportrait orientation, where a maximum coupling inbetween Rx and Tx isgenerated, with a charging current of 800 milliamperes (mA) (labeled“800 mA Portrait” in the sub-diagram (a) of FIG. 4, for brevity),causing the curve shown in the sub-diagram (a) of FIG. 4 to rise andswitch to a higher level. Afterward, the wireless charging receiver 220is put on the wireless charging transmitter 210 in the landscapeorientation, where a minimum coupling inbetween Rx and Tx is generated,with the same charging current of 800 mA (labeled “800 mA Landscape” inthe sub-diagram (a) of FIG. 4, for brevity), causing the curve shown inthe sub-diagram (a) of FIG. 4 to rise again and switch to a higherlevel. This curve may further rise for a certain reason, such as awireless charging strategy of the apparatus 100. In addition, thewireless charging receiver 220 is put on the wireless chargingtransmitter 210 in the portrait orientation with the same chargingcurrent of 800 mA again (labeled “800 mA Portrait” in the sub-diagram(a) of FIG. 4, for brevity), causing the curve shown in the sub-diagram(a) of FIG. 4 to switch back to a lower level that is similar to thelevel between 30 sec and 60 sec. Later, the DVD may be put nearby, soboth of the wireless charging receiver 220 and this DVD are put onto thewireless charging transmitter 210 (labeled “800 mA Portrait 8 cm DVD” inthe sub-diagram (a) of FIG. 4, for brevity), causing the curve shown inthe sub-diagram (a) of FIG. 4 to rise and switch to another higherlevel. At last, the DVD is removed, causing the curve shown in thesub-diagram (a) of FIG. 4 to switch back to a lower level that issimilar to the level between 30 sec and 60 sec.

Although there is only a slight difference between the power loss in thesituation A where the wireless charging receiver 220 is wirelesslycharged in the landscape orientation and the power loss in the situationB where the wireless charging receiver 220 is wirelessly charged in theportrait orientation and the DVD is positioned nearby (e.g. as shown inthe sub-diagram (a) of FIG. 4, the level of the partial curvecorresponding to the situation B and the level of the partial curvecorresponding to the situation A are close to each other along thevertical axis), the curve shown the sub-diagram (b) of FIG. 4 indicatesthat the current deviation can be utilized for distinguishing thesituation B from the situation A or distinguishing the situation A fromthe situation B, and the curve shown the sub-diagram (c) of FIG. 4indicates that the admittance deviation can be utilized fordistinguishing the situation B from the situation A or distinguishingthe situation A from the situation B. For example, as shown in thesub-diagram (b) of FIG. 4, the level of the partial curve correspondingto the situation B and the level of the partial curve corresponding tothe situation A are surely separated from each other along the verticalaxis, and therefore the apparatus 100 (more particularly, the FODstrategy module 130) is capable of distinguishing the situation B fromthe situation A and is capable of distinguishing the situation A fromthe situation B according to the current-related index mentioned above,without being hindered by the fluctuations of the curve shown in thesub-diagram (b) of FIG. 4. In another example, as shown in thesub-diagram (c) of FIG. 4, the level of the partial curve correspondingto the situation B and the level of the partial curve corresponding tothe situation A are surely separated from each other along the verticalaxis, and therefore the apparatus 100 (more particularly, the FODstrategy module 130) is capable of distinguishing the situation B fromthe situation A and is capable of distinguishing the situation A fromthe situation B according to the admittance-related index mentionedabove, without being hindered by the fluctuations of the curve shown inthe sub-diagram (c) of FIG. 4.

Therefore, based on the multi-index control scheme shown in FIG. 4, themethod 300 and the associated apparatus 100 can accurately determinewhether a foreign object is detected regardless of the couplingvariation due to different Rx position, and therefore the related artproblems such as the aforementioned false alarm or the aforementioneddetection failure can be prevented. More particularly, in a situationwhere the wireless charging transmitter is a resonant wireless chargingtransmitter, the method 300 and the associated apparatus 100 canproperly perform FOD (more particularly, the wireless charging FODmentioned in Step 330) with aid of admittance detection and/or impedancedetection.

FIG. 5 illustrates a multi-index control scheme involved with the method300 shown in FIG. 3 according to another embodiment of the presentinvention. The curve in the sub-diagram (a) of FIG. 5 may indicate thewireless charging receiver count parameter (which can be referred to asthe device number or the Rx number in this embodiment, for brevity) thatvaries with respect to time. Please note that the wireless chargingreceiver count parameter represents the number of wireless chargingreceivers within the aforementioned at least one wireless chargingreceiver. In addition, the curve in the sub-diagram (b) of FIG. 5 mayindicate the transmitter power (which can be referred to as the Tx powerin this embodiment, for brevity) that varies with respect to time.Additionally, the curve in the sub-diagram (c) of FIG. 5 may indicatethe transmitter admittance (which can be referred to as the Txadmittance in this embodiment, for brevity) that varies with respect totime, where the admittance-related index of this embodiment correspondsto the ratio of the driving current I_(DRV) to the driving voltageV_(DRV). Further, the curve in the sub-diagram (d) of FIG. 5 mayindicate the transmitter current (which can be referred to as the Txcurrent in this embodiment, for brevity) that varies with respect totime.

For example, the time expressed by the horizontal axis of eachsub-diagram within the sub-diagrams (a), (b), (c), and (d) of FIG. 5 canbe measured in unit of second (sec), and the data values of the dataexpressed by the vertical axis of each sub-diagram within thesub-diagrams (b), (c), and (d) of FIG. 5 may have been scaled up orscaled down (e.g. by utilizing an associated calculation unit in thecorresponding calculation circuit for preparing the data used forgenerating the corresponding index within the index generating module120), in order to prevent the data from being unusable and/or preventthe data from being truncated. This is for illustrative purposes only,and is not meant to be a limitation of the present invention. In someexamples, the unit of the time expressed by the horizontal axis of eachsub-diagram within the sub-diagrams (a), (b), (c), and (d) of FIG. 5 mayvary. In some examples, it is unnecessary to process at least oneportion (e.g. a portion or all) of the data (e.g. the data used forgenerating the corresponding index) by scaling (e.g. scaling up orscaling down).

According to this embodiment, one or more of the wireless chargingreceiver 220, another wireless charging receiver such as a copy of thewireless charging receiver 220, a DVD such as that mentioned above, anda non-compatible electronic device (labeled “iPhone” in FIG. 5, forexample) that is not designed for the wireless charging transmitter 210can be selectively put onto the wireless charging transmitter 210 atdifferent time points. At first, there is no load of wireless charging(e.g. at the time of 0 sec) and none of the wireless charging receiver220, the other wireless charging receiver, the DVD, and thenon-compatible electronic device are not put onto the wireless chargingtransmitter 210. Then, the wireless charging receiver 220 is put ontothe wireless charging transmitter 210 (labeled “1 phone” in thesub-diagram (a) of FIG. 5, for better comprehension), causing the curveshown in any sub-diagram within the sub-diagrams (a), (b), (c), and (d)of FIG. 5, such as the curve shown in a specific sub-diagram within thesub-diagrams (a), (b), (c), and (d) of FIG. 5, to rise and switch to ahigher level. Afterward, both of the wireless charging receiver 220 andthe other wireless charging receiver (e.g. the copy of the wirelesscharging receiver 220) are put on the wireless charging transmitter 210(labeled “2 phone” in the sub-diagram (a) of FIG. 5, for bettercomprehension), causing the curve shown in any sub-diagram within thesub-diagrams (a), (b), (c), and (d) of FIG. 5, such as the curve shownin the specific sub-diagram mentioned above, to rise again and switch toanother higher level. In addition, the other wireless charging receiveris removed and only the wireless charging receiver 220 is put on thewireless charging transmitter 210 (labeled “1 phone” in the sub-diagram(a) of FIG. 5, for better comprehension), causing the curve shown in anysub-diagram within the sub-diagrams (a), (b), (c), and (d) of FIG. 5,such as the curve shown in the specific sub-diagram mentioned above, toswitch back to a lower level that is similar to the level between 20 secand 30 sec. Later, both of the wireless charging receiver 220 and thenon-compatible electronic device are put on the wireless chargingtransmitter 210 (labeled “1 phone+iPhone” in the sub-diagram (a) of FIG.5, for better comprehension), causing the curve shown in any sub-diagramwithin the sub-diagrams (b), (c), and (d) of FIG. 5 to vary as shown inFIG. 5. Afterward, the non-compatible electronic device is removed andonly the wireless charging receiver 220 is put on the wireless chargingtransmitter 210 (labeled “1 phone” in the sub-diagram (a) of FIG. 5, forbetter comprehension), causing the curve shown in any sub-diagram withinthe sub-diagrams (b), (c), and (d) of FIG. 5 to vary as shown in FIG. 5.Additionally, the DVD may be put nearby, so both of the wirelesscharging receiver 220 and this DVD are put onto the wireless chargingtransmitter 210 (labeled “1 phone+DVD” in the sub-diagram (a) of FIG. 5,for better comprehension), causing the curve shown in any sub-diagramwithin the sub-diagrams (b), (c), and (d) of FIG. 5 to vary as shown inFIG. 5. At last, the DVD is removed, causing the curve shown in anysub-diagram within the sub-diagrams (b), (c), and (d) of FIG. 5 to varyas shown in FIG. 5.

Please note that, in this embodiment, a dangerous foreign object such asthe DVD may induce larger power loss than that of a non-dangerousforeign object such as the non-compatible electronic device. Inaddition, the dangerous foreign object such as the DVD may cause thetransmitter transmittance (or the Tx transmittance) to become greater,and the non-dangerous foreign object such as the non-compatibleelectronic device may cause the transmitter transmittance (or the Txtransmittance) to become much greater, where the apparatus 100 (moreparticularly, the FOD strategy module 130) is capable of distinguishingone situation within the situations respectively labeled “1 phone”, “1phone+iPhone”, and “1 phone+DVD” in FIG. 5 from another situation withinthe situations respectively labeled “1 phone”, “1 phone+iPhone”, and “1phone+DVD” in FIG. 5 according to the transmitter transmittance, withoutbeing hindered by the fluctuations of the curve shown in the sub-diagram(c) of FIG. 5. Thus, according to the detected data such as thatindicated by the curves shown in FIG. 5, the apparatus 100 (moreparticularly, the FOD strategy module 130) can control the wirelesscharging transmitter 210 to selectively stop wireless charging whenneeded. In a situation where the foreign objects that will not getheated, such as the non-compatible electronic device in this example,are put nearby, the wireless charging receiver 220 can still bewirelessly charged if the power loss is within a predefined range andthe transmitter admittance (or the Tx admittance) falls within the rangeof an interval corresponding to a predetermined zone that is defined inadvance, such as a specific predetermined zone within the aforementionedat least one predetermined zone.

Therefore, based on the multi-index control scheme shown in FIG. 5, themethod 300 and the apparatus 100 can accurately determine whether aforeign object is detected, and can accurately determine whether aforeign object is a dangerous foreign object or a non-dangerous foreignobject, and therefore the related art problems such as theaforementioned false alarm or the aforementioned detection failure canbe prevented. More particularly, in a situation where the wirelesscharging transmitter is a resonant wireless charging transmitter, thepresent invention method and the associated apparatus can properlyperform FOD (more particularly, the wireless charging FOD mentioned inStep 330) with aid of admittance detection and/or impedance detection,and can temporarily stop a wireless charging procedure when needed, andtherefore can prevent dangerous foreign objects from making fire duringthe wireless charging procedure and can prevent non-dangerous foreignobjects from interrupting the wireless charging procedure. As a result,both of the performance of the wireless charging transmitter and thesafety of the user of the wireless charging transmitter can beguaranteed.

FIG. 6 illustrates a FOD zone involved with the method 300 shown in FIG.3 according to an embodiment of the present invention, where the FODzone shown in FIG. 6 can be taken as an example of the specificpredetermined zone mentioned above. For example, the coordinate plane of(Rx_power, Tx_admittance) mentioned in some embodiments describedbetween the embodiment shown in FIG. 3 and the embodiment shown in FIG.4 can be illustrated as the coordinate plane of (Rx power, Txadmittance) shown in FIG. 6. In addition, the Rx power expressed by thehorizontal axis of FIG. 6 may represent the receiver power of theaforementioned at least one wireless charging receiver, and the Txadmittance expressed by the vertical axis of FIG. 6 may represent thetransmitter admittance mentioned above, i.e. the ratio of the drivingcurrent I_(DRV) to the driving voltage V_(DRV).

In practice, a specific curve on the coordinate plane of (Rx_power,Tx_admittance), such as the curve labeled “Tx estimated admittance @stand. Rx”, can be prepared in advance according to some experiments,for being utilized as the reference for generating the FOD zone, wherethe curve labeled “Tx estimated admittance @ stand. Rx” can be generatedby estimating the Tx admittance with respect to the Rx power while thewireless charging receiver 220 is set at a standard mode (labeled“stand.” in FIG. 6, for brevity).

Please note that the FOD zone indicated by the aforementioned FODcontrol database that is prepared in advance can be utilized forindicating whether a foreign object is a dangerous foreign object or anon-dangerous foreign object. When the received power of theaforementioned at least one wireless charging receiver (i.e. the Rxpower) is just determined according to the aforementioned at least onereceived power report obtained from the aforementioned at least onewireless charging receiver (e.g. the aforementioned received powerreport obtained from the wireless charging receiver 220), based on theaforementioned FOD control database that is prepared in advance, theapparatus 100 may determine, for example, two adjustable thresholds TH1and TH2 by calculating the intersections of the boundary of the FOD zoneand a specific straight line corresponding to the received power that isjust determined, in an online manner. After the two adjustablethresholds TH1 and TH2 are determined in the online manner (e.g. in asituation where TH1<TH2), the apparatus 100 (more particularly, the FODstrategy module 130 therein) may determine whether a foreign object is adangerous foreign object or a non-dangerous foreign object according towhether the latest detection value of the Tx admittance falls within therange of the interval [TH1, TH2]. For example, when it is detected thatthe latest detection value of the Tx admittance falls within the rangeof the interval [TH1, TH2], the apparatus 100 (more particularly, theFOD strategy module 130 therein) may determine this foreign object to bea non-dangerous foreign object; otherwise, the apparatus 100 (moreparticularly, the FOD strategy module 130 therein) may determine thisforeign object to be a dangerous foreign object. As a result, heapparatus 100 (more particularly, the FOD strategy module 130 therein)may determine whether to temporarily stop wireless charging or notaccording to whether this foreign object is a dangerous foreign object.For example, when it is detected that this foreign object is a dangerousforeign object, the apparatus 100 (more particularly, the FOD strategymodule 130 therein) controls the wireless charging transmitter 210 totemporarily stop wireless charging. In another example, when it isdetected that this foreign object is a non-dangerous foreign object, theapparatus 100 (more particularly, the FOD strategy module 130 therein)may control a warning UI such as that mentioned above to indicate thatthis foreign object is a non-dangerous foreign object.

According to some embodiments, the apparatus 100 may use multiple setsof tables (more particularly, multiple sets of LUTs such as the LUTsmentioned above) respectively associated with variant types ofthresholds. For example, the tables may correspond to different valuesof power loss, Tx current, Tx admittance, Tx type, Rx type, etc.,respectively.

FIG. 7 illustrates a FOD strategy control scheme involved with themethod 300 shown in FIG. 3 according to an embodiment of the presentinvention. As shown in FIG. 7, the index generating circuit 122-1 maycomprise an amplifier (labeled “G” in FIG. 7, for brevity) arranged forgenerating the aforementioned power loss index (labeled “Power Loss” inFIG. 7, for brevity), where a gain maybe applied to the power loss indexto process it by scaling (e.g. scaling up or scaling down), in order toachieve a better dynamic range while the power loss index is utilized bythe FOD strategy module 130 (labeled “FOD Strategy” in FIG. 7, forbrevity). In addition, the index generating circuit 122-2 may comprisean amplifier (labeled “G” in FIG. 7, for brevity) arranged forgenerating the aforementioned admittance-related index (labeled“Admittance Deviation” in FIG. 7, for brevity), and more particularly,the aforementioned admittance-related index corresponding to the ratioof the driving current I_(DRV) to the driving voltage V_(DRV), whereanother gain may be applied to the admittance-related index to processit by scaling (e.g. scaling up or scaling down), in order to achieve abetter dynamic range while the admittance-related index is utilized bythe FOD strategy module 130. Additionally, the index generating circuit122-3 may comprise an amplifier (labeled “G” in FIG. 7, for brevity)arranged for generating the aforementioned current-related index(labeled “Current Deviation” in FIG. 7, for brevity), where another gainmay be applied to the current-related index to process it by scaling(e.g. scaling up or scaling down), in order to achieve a better dynamicrange while the current-related index is utilized by the FOD strategymodule 130.

As shown in FIG. 7, the set of FOD strategy control parameters mentionedabove may comprise the aforementioned wireless charging receiver countparameter (which can be referred to as the device number or the Rxnumber in this embodiment, for brevity), and may further comprise theaforementioned at least one device type parameter, such as a transmittertype parameter indicating the aforementioned transmitter type (which canbe referred to as the Tx type in this embodiment, for brevity) and areceiver type parameter indicating the aforementioned receiver type(which can be referred to as the Rx type in this embodiment, forbrevity). For example, the aforementioned transmitter type can be aspecific class of different classes of transmitters, and theaforementioned receiver type can be a specific class of differentclasses of receivers, where a portion of classes within theaforementioned different classes of receivers may correspond todifferent values of receiver impedance (or Rx impedance). In anotherexample, the aforementioned transmitter type can be a specific categoryof different categories of transmitters, and the aforementioned receivertype can be a specific category of different categories of receivers,where a portion of categories within the aforementioned differentcategories of receivers may correspond to different values of receiverimpedance (or Rx impedance). In addition, the set of FOD strategycontrol parameters mentioned above may further comprise the receiverpower (which can also be referred to as the Rx power in this embodiment,for brevity). Additionally, the aforementioned at least one FOD strategy(e.g. one or more FOD strategies) of the FOD strategy module 130 maycomprise utilizing multiple sets of LUTs corresponding to the set ofindexes, and online selecting LUTs that are suitable for the set ofindexes according to the set of FOD strategy control parametersmentioned above. As a result, the FOD strategy module 130 may determinethe aforementioned set of threshold corresponding to the set of FODstrategy control parameters according to the predetermined relationshipbetween the set of threshold and the set of FOD strategy controlparameters, and may compare the set of indexes with the set of thresholdto generate the set of comparison results mentioned above, respectively,and may further generate the aforementioned wireless charging controlsignal (e.g. the output of the FOD strategy module 130 shown in FIG. 1)according to the set of comparison results, for controlling whether totemporarily stop wireless charging or not. This is for illustrativepurposes only, and is not meant to be a limitation of the presentinvention.

Please note that the FOD strategy module 130 may comprise apredetermined logic combination, and may utilize the predetermined logiccombination to perform logic operations (e.g. one or more OR operationsand/or one or more AND operations) according to the set of comparisonresults mentioned above, in order to generate the output of the FODstrategy module 130 shown in FIG. 1, where the predetermined logiccombination may comprise at least one OR logic operation unit (e.g. oneor more OR logic operation units) and/or at least one AND logicoperation unit (e.g. one or more AND logic operation units), such as theOR logic operation unit and the AND logic operation unit shown in FIG.7. For example, the predetermined logic combination can be implementedby hardware circuits, and the predetermined logic combination maycomprise a predetermined combination of logic circuits. Moreparticularly, the OR logic operation unit and the AND logic operationunit shown in FIG. 7 can be implemented with an OR logic gate and an ANDlogic gate, respectively. This is for illustrative purposes only, and isnot meant to be a limitation of the present invention. In anotherexample, the predetermined logic combination can be implemented by aportion of program codes within the aforementioned set of program codesrunning on the processing circuit mentioned above.

With aid of the predetermined logic combination and the online selectedLUTs indicating the set of threshold mentioned above, the FOD strategymodule 130 can accurately perform the wireless charging FOD mentioned inStep 330 and can properly generate the output of the FOD strategy module130 shown in FIG. 1, to control the wireless charging transmitter 210 toaction correctly (e.g. control the wireless charging transmitter 210 tostop wireless charging or continue wireless charging). For example, in asituation where a foreign object (more particularly, a dangerous foreignobject) is detected, the FOD strategy module 130 may control thewireless charging transmitter 210 to stop wireless charging (labeled “Txstop charging” in FIG. 7, for better comprehension). This is forillustrative purposes only, and is not meant to be a limitation of thepresent invention. Please note that the FOD strategy module 130 mayfurther comprise another predetermined logic combination, and mayutilize the other predetermined logic combination to perform logicoperations (e.g. one or more OR operations and/or one or more ANDoperations) according to at least one portion (e.g. a portion or all) ofthe set of comparison results mentioned above, in order to generateanother output of the FOD strategy module 130, where the other output ofthe FOD strategy module 130 can be utilized for controlling a warning UIsuch as that mentioned above (e.g. a warning LED such as that mentionedabove). Thus, with aid of the aforementioned online selected LUTsindicating the set of threshold mentioned above and both of thepredetermined logic combination and the other predetermined logiccombination (labeled “Multiple threshold tables+detection logic” in FIG.7, for better comprehension), the FOD strategy module 130 can accuratelyperform the wireless charging FOD mentioned in Step 330 and can properlygenerate the output of the FOD strategy module 130 shown in FIG. 1 andthe other output of the FOD strategy module 130, to control the wirelesscharging transmitter 210 to action correctly (e.g. control the wirelesscharging transmitter 210 to stop wireless charging or continue wirelesscharging, and selective control the warning UI).

For example, in a situation where a dangerous foreign object isdetected, the FOD strategy module 130 may control the wireless chargingtransmitter 210 to stop wireless charging (labeled “Tx stop charging” inFIG. 7, for better comprehension). In another example, in a situationwhere a safe foreign object (i.e. a non-dangerous foreign object) isdetected, the FOD strategy module 130 may control the wireless chargingtransmitter 210 to keep wireless charging (labeled “Tx keep charging” inFIG. 7, for better comprehension), and may further control the warningUI (e.g. the warning LED) to indicate that this foreign object is anon-dangerous foreign object. In another example, in a situation wherenon-foreign object is detected (e.g. no foreign object is detected), theFOD strategy module 130 may control the wireless charging transmitter210 to keep wireless charging (labeled “Tx keep charging” in FIG. 7, forbetter comprehension). For brevity, similar descriptions for thisembodiment are not repeated in detail here.

FIG. 8 illustrates a wireless charging recovery scheme involved with themethod 300 shown in FIG. 3 according to an embodiment of the presentinvention. According to this embodiment, the apparatus 100 may comparean initial Tx current (more particularly, the current value Ta of theinitial Tx current) that is stored in a memory thereof with the presentTx current (more particularly, the current value T of the present Txcurrent) to determine whether a foreign object has been removed.

As shown in FIG. 8, when the FOD state (e.g. a state indicating that aforeign object is detected) is trigged (or asserted), the apparatus 100may control the wireless charging transmitter 210 to stop wirelesscharging, and more particularly, to stop charging by keeping thewireless charging transmitter 210 in a strobe mode. At this moment, theapparatus 100 may control the wireless charging transmitter 210 tooutput a series of strobe currents, such as the initial Tx currenthaving the current value Ta and the present Tx current having thecurrent value T. More particularly, when the FOD state is triggered (orasserted), the apparatus 100 may store the current value Ta of theinitial Tx current in the memory. The current values of the series ofstrobe currents may decrease as time goes by. When it is detected thatthe difference between the current value Ta of the initial Tx currentand the current value of one of the series of strobe currents, such asthe current value T of the present Tx current, is greater than apredefined value Tb (e.g. Ta−T>Tb), which means the foreign object hasbeen removed, the apparatus 100 may control the wireless chargingtransmitter 210 to resume charging (e.g. normal wireless charging).

FIG. 9 illustrates a random mode device control scheme involved with themethod 300 shown in FIG. 3 according to an embodiment of the presentinvention. According to this embodiment, the apparatus 100 may determinethe random mode device number, i.e. the device number of the wirelesscharging receivers that are operating in a random mode, such as theaforementioned specific wireless charging receiver that may send theaforementioned at least one random phase-delay packet. In the randommode, any of these wireless charging receivers may send randomphase-delay packets such as the aforementioned at least one randomphase-delay packet, and may perform in-band communications (which can bereferred to as inband COMMs in some embodiments, for brevity). For someimplementation details regarding the random mode, please refer to theU.S. Provisional Application No. 61/928,093, which was filed on Jan. 16,2014.

For example, the packet information mentioned above can be accumulatedin the aforementioned predefined period such as a predefined period T,which can be greater than or equal to twice the slot time in the randommode. That is, the predefined period T can be greater than or equal totwice the period of the periodical time slots utilized by any of thesewireless charging receivers. More particularly, a packet detectionmodule (labeled “Packet Detection” in FIG. 9, for brevity) within thewireless charging transmitter 210 may send a value, such as a logicalvalue indicating that a random phase-delay packet is detected, into theupper path of the architecture shown in FIG. 9, to allow this value tobe processed by (or allow this value to go through) some boundaryprotection units such as an initialization control and dump unit(labeled “INT/DUMP” in FIG. 9, for brevity) and a comparison unit(illustrated with a threshold detection function on the upper path ofthe architecture shown in FIG. 9, for example). In addition, theprocessing result from these boundary protection units can be sent intoan amplifier (labeled “G” on the upper path of the architecture shown inFIG. 9, for brevity) for being processed by scaling (e.g. scaling up orscaling down), where the processing result from this amplifier can befiltered by an IIR low pass filter (labeled “IIR” on the upper path ofthe architecture shown in FIG. 9, for brevity), and further filed by ahysteresis unit and a deglitch unit (respectively labeled “HYS” and“DEG” on the upper path of the architecture shown in FIG. 9, forbrevity), in order to determine an anticipated device number such as thedevice number mentioned above. Please note that the lower path of thearchitecture shown in FIG. 9 may comprise some components that aresimilar to some components on the upper path of the architecture shownin FIG. 9, such as another comparison unit, another amplifier, andanother IIR low pass filter, where a power detection module (labeled“Power Detection” in FIG. 9, for brevity) within the wireless chargingtransmitter 210 may obtain the power information from the packetinformation such as that mentioned above (e.g. the power informationcarried by the aforementioned at least one random phase-delay packet,and more particularly, the power information carried by randomphase-delay packets of these wireless charging receivers) to allow thepower information to be processed by the other comparison unit, theother amplifier, and the other IIR low pass filter, in order to generatean average power value of all of these wireless charging receivers. As aresult of the multiplying operation performed by the multiplying unitshown around the lower right corner of FIG. 9, such as the operation ofmultiplying the average power value by the device number, thearchitecture shown in FIG. 9 determines the total device power (labeled“Devices Power” in FIG. 9, for brevity), i.e. the total received powerof these wireless charging receivers, where the total received power canbe taken as an example of the received power of the aforementioned atleast one wireless charging receiver, and can be taken as an example ofthe Rx power shown in FIG. 7.

FIG. 10 illustrates a steady state control scheme involved with themethod 300 shown in FIG. 3 according to an embodiment of the presentinvention. For achieving better performance of the wireless chargingtransmitter 210, the apparatus 100 may perform steady state detection todetermine whether the wireless charging transmitter 210 is in a powertransfer steady state. More particularly, some judgment operationsregarding the aforementioned wireless charging FOD need to be performedin the power transfer steady state.

As shown in FIG. 10, multiple parameters of the wireless chargingtransmitter 210 and/or the aforementioned at least one wireless chargingreceiver, such as the rectified voltage Vrect of the wireless chargingreceiver 220, the transmitter driving voltage such as the drivingvoltage V_(DRV), and the transmitter current (respectively labeled “RxVrect”, “Tx Vin”, and “Tx current” in FIG. 10, for brevity), can bemonitored by the architecture shown in FIG. 10. For example, thearchitecture shown in FIG. 10 can be positioned within the wirelesscharging transmitter 210, and more particularly, can be positionedwithin the apparatus 100. In addition, each of these parameters can befiltered by a lower pass filter (LPF) for deglitching, and can befiltered by a high pass filter (HPF) for offset reduction or offsetelimination, and can further be filtered by a comparison unit(illustrated with a threshold detection function on the correspondingpath within the three paths of the architecture shown in FIG. 10, forexample). For example, the rectified voltage Vrect of the wirelesscharging receiver 220 can be filtered by the LPF LPF1 and the HPF HPF1,the transmitter driving voltage can be filtered by the LPF LPF2 and theHPF HPF2, and the transmitter current can be filtered by the LPF LPF3and the HPF HPF3. Additionally, all of these filtered results are sentto an AND logic operation unit (e.g. an AND logic gate, or an AND logicoperation unit implemented by program code(s) running on the processingcircuit mentioned above), and this AND logic operation unit performs anAND logic operation on these filtered results to generate a power stableindex (labeled “Power Stable” in FIG. 10, for brevity) for indicatingwhether the wireless charging transmitter 210 is in the power transfersteady state. For example, as a result of applying the steady statecontrol scheme shown in FIG. 10 to the apparatus 100, when thefluctuations of each of the outputs of the HPFs HPF1, HPF2, and HPF3 arewithin a predetermined range such as the predetermined range ΔY1 shownin FIG. 10 for a predetermined time period such as the predeterminedtime period ΔT shown in FIG. 10, each of these filtered results are atthe TRUE state thereof (e.g. at the high level thereof), and thereforethe AND logic operation unit outputs the TRUE state thereof (e.g. at thehigh level thereof), causing the power stable index to indicate that thewireless charging transmitter 210 is in the power transfer steady state.

FIG. 11 illustrates an emergency protection control scheme involved withthe method 300 shown in FIG. 3 according to an embodiment of the presentinvention. According to this embodiment, the apparatus 100 may performemergent FOD according to the other set of indexes mentioned above,without being limited by any judgment within the FOD associated to theset of indexes mentioned above or by the steady state detectionmentioned above. As shown in FIG. 11, each of the Tx current and Txadmittance can be monitored (or filtered) by utilizing a comparison unit(illustrated with a threshold detection function on the correspondingpath within the two paths of the architecture shown in FIG. 11, forexample). For example, when one or more of the Tx current and Txadmittance (e.g. Tx current, or Tx admittance, or both of the Tx currentand Tx admittance) is at the TRUE state thereof (e.g. at the high levelthereof), and the OR logic operation unit outputs the TRUE state thereof(e.g. at the high level thereof), causing the emergency state FOD indexat the output of the architecture shown in FIG. 11 to indicate that thewireless charging transmitter 210 is in the emergency state. As aresult, the wireless charging transmitter 210 may stop wireless chargingwhen the Tx current reaches a first predetermined value or Tx admittancereach a second predetermined value, where each of the firstpredetermined value and the second predetermined value may correspond toRx number shown in FIG. 7 (i.e. the device number mentioned above) andthe Rx power shown in FIG. 7.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method for performing wireless chargingcontrol, the method being applied to a wireless charging transmitter,the method comprising the steps of: performing current detection andvoltage detection to monitor a driving current and a driving voltagewithin the wireless charging transmitter, respectively, wherein thedriving current and the driving voltage are utilized for driving a poweroutput coil of the wireless charging transmitter; generating a set ofindexes at least according to the driving current and the drivingvoltage, wherein the set of indexes comprises a power loss indexindicating power loss of a wireless charging operation performed by thewireless charging transmitter, and further comprises anadmittance-related index corresponding to any of a ratio of the drivingcurrent to the driving voltage or a reciprocal of the ratio of thedriving current to the driving voltage; and performing wireless chargingforeign object detection (FOD) according to the set of indexes.
 2. Themethod of claim 1, wherein the step of generating the set of indexes atleast according to the driving current and the driving voltage furthercomprises: determining charging power output from the wireless chargingtransmitter according to the driving current and the driving voltage;determining received power of at least one wireless charging receiveraccording to at least one received power report obtained from the atleast one wireless charging receiver; and generating the power lossindex according to the charging power output from the wireless chargingtransmitter and according to the received power of the at least onewireless charging receiver.
 3. The method of claim 1, wherein in asituation where the admittance-related index corresponds to the ratio ofthe driving current to the driving voltage, the step of generating theset of indexes at least according to the driving current and the drivingvoltage further comprises: determining received power of at least onewireless charging receiver according to at least one received powerreport obtained from the at least one wireless charging receiver;determining a normalized transmitter admittance parameter correspondingto the received power of the at least one wireless charging receiveraccording to a predetermined relationship between the normalizedtransmitter admittance parameter and the received power of the at leastone wireless charging receiver; and calculating a difference between theratio of the driving current to the driving voltage and the normalizedtransmitter admittance parameter to generate the admittance-relatedindex.
 4. The method of claim 1, wherein in a situation where theadmittance-related index corresponds to the reciprocal of the ratio ofthe driving current to the driving voltage, the step of generating theset of indexes at least according to the driving current and the drivingvoltage further comprises: determining received power of at least onewireless charging receiver according to at least one received powerreport obtained from the at least one wireless charging receiver;determining a normalized transmitter impedance parameter correspondingto the received power of the at least one wireless charging receiveraccording to a predetermined relationship between the normalizedtransmitter impedance parameter and the received power of the at leastone wireless charging receiver; and calculating a difference between thereciprocal of the ratio of the driving current to the driving voltageand the normalized transmitter impedance parameter to generate theadmittance-related index.
 5. The method of claim 1, wherein the set ofindexes further comprises a current-related index corresponding to thedriving current, wherein the current-related index is different from theadmittance-related index.
 6. The method of claim 5, wherein the step ofgenerating the set of indexes at least according to the driving currentand the driving voltage further comprises: determining received power ofat least one wireless charging receiver according to at least onereceived power report obtained from the at least one wireless chargingreceiver; determining a normalized transmitter current parametercorresponding to the received power of the at least one wirelesscharging receiver according to a predetermined relationship between thenormalized transmitter current parameter and the received power of theat least one wireless charging receiver; and calculating a differencebetween the driving current and the normalized transmitter currentparameter to generate the current-related index.
 7. The method of claim1, wherein the step of performing the wireless charging FOD according tothe set of indexes further comprises: determining a set of thresholdcorresponding to a set of FOD strategy control parameters according to apredetermined relationship between the set of threshold and the set ofFOD strategy control parameters; comparing the set of indexes with theset of threshold to generate a set of comparison results, respectively;and generating a wireless charging control signal according to the setof comparison results, for controlling whether to temporarily stopwireless charging or not.
 8. The method of claim 7, wherein the step ofperforming the wireless charging FOD according to the set of indexesfurther comprises: generating a warning control signal according to atleast one portion of comparison results within the set of comparisonresults, wherein the warning control signal is utilized for controllinga warning user interface (UI) of the wireless charging transmitter toindicate whether a foreign object is a dangerous foreign object or anon-dangerous foreign object.
 9. The method of claim 7, wherein the setof FOD strategy control parameters comprises a received power parameter,wherein the received power parameter corresponds to received power of atleast one wireless charging receiver.
 10. The method of claim 9, whereinthe set of FOD strategy control parameters further comprises a wirelesscharging receiver count parameter, wherein the wireless chargingreceiver count parameter represents a number of wireless chargingreceivers within the at least one wireless charging receiver.
 11. Themethod of claim 10, wherein the set of FOD strategy control parametersfurther comprises at least one device type parameter, wherein the atleast one device type parameter corresponds to a transmitter type of thewireless charging transmitter or at least one receiver type of the atleast one wireless charging receiver.
 12. The method of claim 10,wherein a specific wireless charging receiver within the at least onewireless charging receiver determines at least one random value forcontrolling timing of packet transmission regarding at least onewireless charging report of the specific wireless charging receiver;based on the at least one random value, the specific wireless chargingreceiver sends at least one random phase-delay packet, wherein eachrandom phase-delay packet of the at least one random phase-delay packethas a random phase-delay with respect to a time slot, and the at leastone random phase-delay packet is utilized for carrying information ofthe at least one wireless charging report; and the step of performingthe wireless charging FOD according to the set of indexes furthercomprises: accumulating packet information of a plurality of packets ina predefined period to generate an accumulation value, wherein theplurality of packets comprises the at least one random phase-delaypacket sent by the specific wireless charging receiver, and a length ofthe predefined period is greater than or equal to twice a length of thetime slot; and determining the wireless charging receiver countparameter according to the accumulation value.
 13. The method of claim12, wherein the step of determining the wireless charging receiver countparameter according to the accumulation value further comprises:performing at least one filtering operation on the accumulation value togenerate the wireless charging receiver count parameter.
 14. The methodof claim 1, wherein the step of performing the wireless charging FODaccording to the set of indexes further comprises: accessing a FODcontrol database that is prepared in advance, wherein the FOD controldatabase indicates at least one predetermined zone on a coordinate planeof (Rx_power, Tx_admittance), in which the coordinate Rx_powerrepresents received power of at least one wireless charging receiver andthe coordinate Tx_admittance represents the ratio of the driving currentto the driving voltage, and the at least one predetermined zonecorresponds to dangerous foreign objects or non-dangerous foreignobjects; and based on the FOD control database, determining whether totemporarily stop wireless charging or not according to the receivedpower of the at least one wireless charging receiver and the ratio ofthe driving current to the driving voltage.
 15. The method of claim 1,wherein the set of indexes is generated in a steady state regarding thewireless charging operation performed by the wireless chargingtransmitter; and the method further comprises: performing at least onesteady state detection within the wireless charging transmitter toguarantee that the set of indexes is generated in the steady state. 16.The method of claim 1, further comprising: generating another set ofindexes at least according to the driving current and the drivingvoltage, wherein the other set of indexes comprises a current indexindicating the driving current, and further comprises an admittanceindex indicating the ratio of the driving current to the drivingvoltage; wherein the step of performing the wireless charging FODaccording to the set of indexes further comprises: performing thewireless charging FOD according to the set of indexes and according tothe other set of indexes.
 17. The method of claim 16, wherein the stepof performing the wireless charging FOD according to the set of indexesand according to the other set of indexes further comprises: when theother set of indexes indicates that a dangerous foreign object isdetected, immediately stopping wireless charging and temporarilypreventing utilizing the set of indexes.
 18. An apparatus for performingwireless charging control, the apparatus comprising at least one portionof a wireless charging transmitter, the apparatus comprising: at leastone detection circuit, arranged for performing current detection andvoltage detection to monitor a driving current and a driving voltagewithin the wireless charging transmitter, respectively, wherein thedriving current and the driving voltage are utilized for driving a poweroutput coil of the wireless charging transmitter; a set of indexgenerating circuits, coupled to the at least one detection circuit,arranged for generating a set of indexes at least according to thedriving current and the driving voltage, wherein the set of indexescomprises a power loss index indicating power loss of a wirelesscharging operation performed by the wireless charging transmitter, andfurther comprises an admittance-related index corresponding to any of aratio of the driving current to the driving voltage or a reciprocal ofthe ratio of the driving current to the driving voltage; and a foreignobject detection (FOD) strategy module, coupled to the set of indexgenerating circuits, arranged for performing wireless charging FODaccording to the set of indexes.
 19. A method for performing wirelesscharging control, the method being applied to a wireless chargingtransmitter, the method comprising the steps of: performing currentdetection and voltage detection to monitor a driving current and adriving voltage within the wireless charging transmitter, respectively,wherein the driving current and the driving voltage are utilized fordriving a power output coil of the wireless charging transmitter;generating a set of indexes at least according to the driving currentand the driving voltage, wherein the set of indexes comprises a powerloss index indicating power loss of a wireless charging operationperformed by the wireless charging transmitter, and further comprises acurrent-related index corresponding to the driving current; andperforming wireless charging foreign object detection (FOD) according tothe set of indexes.
 20. A method for performing wireless chargingcontrol, the method being applied to a wireless charging transmitter,the method comprising the steps of: performing current detection andvoltage detection to monitor a driving current and a driving voltagewithin the wireless charging transmitter, respectively, wherein thedriving current and the driving voltage are utilized for driving a poweroutput coil of the wireless charging transmitter; generating a set ofindexes at least according to the driving current and the drivingvoltage, wherein the set of indexes comprises an admittance-relatedindex corresponding to any of a ratio of the driving current to thedriving voltage or a reciprocal of the ratio of the driving current tothe driving voltage, and further comprises a current-related indexcorresponding to the driving current; and performing wireless chargingforeign object detection (FOD) according to the set of indexes.